Work-carrying device for grinding machines



March 2 W. D. ARCHEA WORK CARRYING DEVICE FOR GRINDING MACHINES Filed Jan. 16, 1924 `3 Sheets-Sheet l W. D. ARCHEA woRx CARRYING DEVICE Foa GRINDING March 2 1926.

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1,575,520 w. D. ARCHI-:A

WORK CARRYING DEVICE FOR GRINDING MACHINES Filed Jan. 16, 1924 S'Sheets-Sheet 5 Patented Mar. 2, 1926.

UNITED STATES 1,575,520 PATENT OFFICE.

WALTER D. ARCHEA, OF NORWOOD, OHIO, ASSIGNOR TO THE CINCINNATI MILLING MACHINE COMPANY, OF CINCINNATI, OHIO, A CORPORATION OF OHIO.

WORK-CARRYING DEVICE FOR'GBINDING MACHINES. y

Application led January 16, 1924. Serial No. 686,653.

To all whom it may concern.' l

Be it known that I, lVALTEn D. ARGHEA. a citizen of the United States, residing at Norwood, in the county of Hamilton and State of Ohio, have invented certain new and useful Improvements in Vork-Carrying Devices for Grinding Machines, of which the following isa specification.

'lhis invention pertains to machines for grinding objects or portions of objects to circular form in cross section, either cylindrical or tapering, and has reference particularly to means for introducing such objects into and withdrawing them from grinding position between a grinding wheel or disk and a coacting wheel or disk which effects. or governs, or effects and governs, the rotation of the object ground.

A special feature of the invention resides in means for holding the work or object treated upon the rest or support which sustains it at proper level while being ground, such holding means being designed to permit the passage of an enlargement, head or shoulder of the work or object u p to the grinding member.

The invention is illustrated in the accompanying drawings, in which: Figure 1 is a side elevation of a grindmg machine of one of the types in connection with which the present invention may be advantageously employed:

Figure 2 is a transverse sectional view on the line 2--2 of Figs. 3 and 4L;

Figure 3 is a front elevation of the feeding device or attachment looking towardv the grinding wheel. the bed or base of the machine and the slide which carries the governing wheel being shown in section:

Figure 4 is a top plan view of the device showing its relation to the grinding and the governing or regulatingwheels;

Figure 5 is a plan view of parts of the device of Fig. 4, shown on an enlarged scale and with the work or blank in grinding po-A sition:

Figure 6 is an end elevation of the feeding device, sufficient of the grindingand governing wheels being shown to indicate the relation of said feeding device thereto.

The mechanism here illustrated and about to be described is designed for use with grinding machines employing a grinding wheel, disk or element; a governing wheel, disk or element; and en interposed workrest or support u on which the object to be ground rests and liy which it is sup orted in proper relation to the grinding an governmg elements While being ground. Such machines are commonly designated as centerless grinders because the work piece is not mounted on centers. There are various types of centerless grinders di'ering from each other primarily in the forms vof the grinding element and the governing elementand in the way in which these elements are presented to the work piece. All centerless grinders have in common the characteristics that these two elements are opposed to each other, that the work rest extends between the opposed faces, and that the relative speeds of the grinding and governing elements are so chosen that the governing element regulates the rotation of the work piece and the grinding element grindsthe work piece as the latter rotates. In the particular type of machine here illustrated, the grinding and governing wheels or elements are peripherally opposed, and the work-rest or support extending betweenr them serves to support the work while being rotated through frictional contact with the relatively slow-turning governing wheel, and while being ground by the rapidly turning grinding wheel. To effect this action the two wheels rotate in the same direction about their 'respective axes, (clockwise as viewed in Figs. 2 and 6 of the accompanying drawings), so that the grinding wheel is caused to move downward relatively to the work-rest and work, and the governing or regula-ting wheel is caused to move upward relatively thereto.

Another known type of centerless grinder uses disks which grind on their side faces. The disks are usually made slightly conoidal or infrusto-conical form, and their shafts or arbors are set at a slight inclination one to the other, so that while the disks stand face to face throughout their area, said faces diverge at one side of their axes but are parallel at the opposite side thereof along a given line or plane, is the plane of contact of said disks with opposite sides of lthe work or blank being ground. The

work-rest in such cases extends between the opposed conoidal faces at that side of their axes on which said faces areparallel in the grinding plane, and the disks rotate in opposite directions about their respective axes in order that'the grinding disk shall move downwa-rd toward the work and work-rest, and that the governing or regulating member shall move upward relatively thereto.

In another known type of centerless grinder using face grmding disks, the grinding disk and the governing disk are carried by shaftsor arbors whose axes are parallel, or substantially so, but offset so that the two disks overlap to approximately one-half their diameter. Under such arrangement the disks will rotate in the same direction about their axes to secure a downward movement of the grinding wheel and an upward movement of the governing or regulating wheel relatively to the work-rest and work. Here again the work rest extends between the opposed faces.

In still other forms of centerless grinding machines the two elements are set in angular relation one to the other, that is to say, their arbors or shafts stand in 90 vdegree, or substantially 90 degree, relation one to the other, and the periphery of one wheel is opposed to the side or radial face of the other. In such relation tho grinding member or element moves downward toward the work-rest or support and the governing or regulating member nieves upward, and in all these various relations o-f the` grinding and governing elements this downward movement of the grinding and upward movement of the governing element is maintained, the grinding element being caused to move at high velocity, and the governing or regulating element at relatively low velocity or surface speed. In this case also the Work rest extends between the opposed faces.

The 'present invention relates primarily to the work supporting means and is available for use in the form shown or with only minor modifications in centerless grinders of any of the types above enumerated. Generallyv stated, this work supporting means is available for use in any centerless grinding machine where the grinding and regulating members are so opposed as' to offer a grinding passage through which the work carrier may extend and are so driven that one serves to regulate the ro-tation of the work piece on such carrier while the other abrad'es the rotating work piece. The type of centerless grinder making use of peripherally opposed wheels is generally regarded as the most satisfactory and for that reason has been chosen for illustrative purposes.

Referring again to the drawings and first to Fig. 1` the numeral 1 indicates the main frame or base of the machine which is preferably of hollow box construction.- 2 indicates the grinding wheel and 3 the governing or regulating wheel which, acting in 95 connection with the work-rest 4, and the grinding wheel 2, determines the speed of rotation of the blankor work 5. The grinding and governing elements 2 and 3 are mounted upon shafts or arbors, and rotated at suitable relative s eeds by belts passing about pulleys on said) arbors or shafts; by gearing; or in any other usual and convenient Way of imparting motion to rotary bodies. The shafts or arbors of the wheels 2 and 3 are carried in suitable bearings of 75 supports, either at one or at both sides of the respective wheels, but preferably in the form of long sleeve bearing at one side to facilitate mounting the wheels upon their respective shafts or arbors and removing them therefrom without disturbing the bearings and shafts.

The bearing or bearings for the grinding wheel may be made adjustable if desired to permitmovement of said wheel toward and 3v from the governing or regulating wheel, but in practice I prefer that it or they be fixed in position, since it is of great importance that the grinding wheel mountings be as rigid as possible to the end that there shall be little or no vibration created by the high speed of rotation of said wheel. This is further ensured by perfect truing and centering of the wheel, best attainable with peripheral grinders.

In the machine as illustrated in Fig. l the shaft of the governing or regulating wheel 3 is carried in a bearing or bearings mounted upon and movable with a slide 6 capable of adjustment toward and from the grinding wheel 2 by' a screw-shaft 7 provided with a hand-wheel or spoke-wheel 8 by which to turn it in one or the other direction as required.

Various parts and features of the machine indicated in outline in Fig. 1 are not of my invention and will not be here described, but the general features and principle of the machine have been thus outlined to give a better understanding of the relation of the feeding device here set forth to the other parts of the machine.

The device for supporting and guiding the work and introducing it into and withdrawing it from grinding position is preferably carried by the slide 6, which as stated carries the ,bearing or bearings of the governing or regulating wheel, but'it may be mounted upon the main frame or bed 1 of the machine if desired. This supporting, guiding and feeding mechanism comprises a supporting or guiding member 9 in the form of a bar or block secured by bolts 10 to the slide 6 or to the bed-plate of main frame 1, with its length at right angles to the direction of movement of slide 6. or parallel with the axis of the .grinding wheel 2. This support 9 is advisably of the form shown in Figs. 2 and 6 having vertical longitudinal walls beveled, 0r out away in their 13 upper portions as seen in said figures, leaving a relatively narrow top portion horizontal. This top portion-is channeled to receive a hardened, grooved bar or runway 11 for anti-friction balls or rollers 12, upon which rests and travels a similar hardened bar or runway 13 seated in a groove in a carriage 14 which straddles or encompasses the supporting baror block 9 and moves longitudinally thereon. -The depending walls of the carriage 14, which are slightly set away from the parallel walls of the guide block or bar 9 to afford due clearance, are provided on their inner faces with channeled bars 15 to receive anti-friction balls or rollers 16 which are retained Within the grooves or bars 15by plates 17 secured in place by screws 18. (lo-acting bars or runways 19 1ct into grooves or recesses 1n the longitudinal upright walls of the guide block or bar 9 complete the ball races or runways, and stops or retainers are provided to prevent escape of the balls at the ends of .the bars 11 and 19, one of said stops 27 being shown in dotted lines in Fig. 3. The bars 19 may be held in their seats or grooves by i screws 20, as shown in connection with the left-hand bar in Fig. 2, or by spring-pressed beveledplugs 21 as shown at the right-hand side, such holding devices permitting removal of the bars 19 incase they become worn and require renewal or dressing.

The sides of thecarriage 14 are in their upper portions curved or fashioned to conform more or less closely to the curvature of the Wheels 2 and 3 which they respectively face, thus giving tothe upper portion of said carriage a narrowing or wedge-like' form, permitting it to extend well up into the space between the grinding wheel 2 and the governing or regulating wheel 3. The

face of said carriage opposed to the periphery of the governing wheel 3 is further cut away to afford a seat for the workrest ,or support 4, here shown as a flat steel bar, the upper portion of which is beveled or chamfered to produce a thin edge nearest the periphery ofthe grinding wheel 2, from which point it slopes downward toward the perlphery of the governing wheel 3. The work-rest 4 is'held firmly to its4 seat on the carriage 14 by a clamping plate 22, fashioned as shownin Fig. 2 with a rounded bead or bearing edge at its lower boundary, which forms a fulcrum or swinging point forV the plate, and with an overhanging lip or edge at its upper boundary to giveI a relatively narrow face Where it bears against the work-rest. The clamping plate 22 is drawn toward and held firmly against the work-rest; by screws 23, one of which is seen in Fig. 2.

By providing a plurality of work-rest plates or bars 4 of dilerent width: thickness, and form of upper-edge, the device may be readily adapted to support objects of different size, form and material, and of varying shape, as a cylinder of uniform diameter throughout, or of two or more diameters in di'ercnt portions of its length, or of conical or taper form, all of which may be ground in machines such as here indicated.. if the grinding and governing wheels be properly formed and adjusted. This is mentioned here for the purpose merely of indicating the range of use ofthe feeding and withdrawing'device or mechanism described and claimed, but no claim is made in this application to such formation of` wheels or such variant grinding per se.

The carriage .14 is made considerably longer than the support 9, and isjdesigned to move upon and relatively to said support a distance somewhat in excess of the length of the objects to be presented by it to' the grinding and regulatmg wheels. It is provided at its outer end with a handle 24 by which it may be manually moved longitudinally, and it is furnished at its ends with screws :25 and jam-nuts 26, formin stops to limit the .travel of the carriage 1n both directions. nuts 26 are preferably circular and knurled as indicated, to permit them to be adjusted. without the use of tools or wrenches, and the threads are of slight pitch to afford deli-` cate and accurate adjustment. The' carriagev The heads of screws 25 and the Ase in adjusted position in said block a slit 31 (seeFig. 6) extends from the stem-receiving opening to the side of the block, and a pinch-screw 32 passing through an opening in the upper arm thus formed andscrewing into a tapped hole in the lower arm of block 28, serves to draw the arms together and to clamp or bind the stem 30 in place.

Through the end of the stem-30 toward the wheels 2 and 3 therewis formed a hole to receive an- L-shaped rest or support 33 which may be vertically adjusted, and when so adiusted is clamped by a set-'screw 34. The oiiice of this rest is to support the outer end of the object to be ground, whether that be a plain cylinder of a head or projection of any kind. a hexagon head being indicated in Fig. 5. The stem 30 may be turned in its seat preparatory to being clamped, so that the horizontal arm at its-lower end may be indicates a bar provided with a horizontal wing or plate 36 furnished with slots 37 by which the plate and bar are made horizontally adjustable toward and from the upper portion of the carriage14, screws 38 passing through said slots and into tapped holes in the top of the carriage 14 serving when turned down, to clamp and bind the plate 36 in its adjusted position. The bar 35 extends parallel with and preferably somewhat beyond the stem 30, as best shown in Figs. 4 and 5, and serves in addition to other offices, to form a second support for the outer end or head of the object ground, as indicated in Fig. 5. When the stem 30, rest 33, and bar 35 are suitably adjusted they hold' or support the head or outer end of the work in proper position relatively to the work-rest 4 and to the grinding and regulating wheels, but until the leading end of the object enters the grinding space between the grinding wheel 2 and the governing or regulating wheel 3 it is necessary to furnish a lateral support to said work on the side next said governing wheel. While a suitably formed groove in the upper edge of the work-rest bar 4 might serve this purpose, the groove would be liable to receive and retain minuteparticles of metal ground from the object treated, or granules or crystals loosened from lthe grinding or the regulating wheel, and these would tend to cut or mar the surface of the object ground, and by making the sup ort uneven would tend to prevent the grin in of the object to true and uniform shape an dimensions. On the other hand, it is dilicult if not impracticable to provide a retaining guard or support foi` that side of the object next the regulating wheel, which shall at once give adequate support to the object, prevent its falling from the rest, and yet pass into the opening between the grinding and the regulating or governing Wheel.

I therefore provide a support which is moved back automatically as the object treated moves inward to grinding posit-ion, or into the'space between the grinding and governing wheels. This device consists essentially of one or more, usually severa-l, swinging arms or supports, the bearing or supporting face of each of which stands normally in a vertical plane co-incident with the side of the object nearest the governing or regulating wheel, said arms being normally held in such position, but moved back on the inward or forward movement of the carriage by the bar 35 or other suitable means. This mechanism is shown in Figs. 2 to 6 inclusive. It is mounted upon and sup orted by a ost or bracket 39 bolted or ma e fast to a epending lug or pro'ection 40 extending downward and outwar from the carriage-supporting member 9, as seen in Fig. 6. The top of bracketl 39, which is horizontal, extends in the direction of the travel of the carriage and at right angles thereto, to an extent sufficient to afford an' adequate bearing face for the bottom plate 41 of a substantially Z-shaped bracket 42, slotted as shown in Figs. 3, 4 and 6 to pei'- mit horizontal adjustment toward and from the body of carriage 14 when the clamping screws '43 are backed or loosened, such adjustment being effected preferably by a screw 44 entering a tapped hole in the bottom plate 41, and having a spool-shaped or cii'cumferentially grooved head 45 seated in a forked arm 46 of the post 39. The flanges of the spool-like head 45 prevent axial movement of the screw 44, which conse uently moves the plate 41 inward or outwar when rotated in one or the other direction.

The Z-sha-ped bracket 42 has upper and lower bars or flanges 47, 48, on the side toward the carriage 14, in which are journaled or mounted to tui'n, vertical stems 49 of cylindrical form through the major portion of their length. Each stem 49 carries at its upper end an arm 50 4preferably of the form shown in Fig. 2, terminating at its outer or free end im a substantially vertical section or member which bears against and gives support to the work lying on workrest 4, as shown in Figs. 2 and 5 and by dotted linesin Fig. 6. In Fig. 5 but one arm 50 is shown in supporting position, the object treated being there shown with its outer or trailing end somewhat close to the in-feedin side of the grinding and governing whees, and the need for such support being at such time slight.

Encircling each of the stems 49 is a helical sprin 51, one end of which is made Vfast to a. fixe support, preferably the flange or bar 47 of the Z-shaped bracket 42, while the other en'd is clamped or made fast to the stem in any convenient way, a binding screw 52 forthis purpose being Shown in Fig. 2. The springs 51 are arranged to swing the arms 50 toward the work-rest or bar 4, and the movement of each arm in that direction is limited by a stop-screw 53 .with which engages a stud 54 projecting radially from the stein 49. The adjusting screw 53 is advisably provided with a jam-nut 55. The swinging arms 50, viewed from above, are preferably of the outline shown in Figs. 4 and 5; that is to say, they have between their carrying vstems 49 and the upright terlinitial member, a rounded projection 56 with which the forward or inner end of the bar 35 makes contact las the carriage 14 moves toward the grinding and the' governing wheels.

When the work is positioned on the workrest or bar 4 and support 33 in contact with the u standin ends of the swinging arms 50, a roper y ad'usted, the .carriage 14. 1s movA inward an the-leading end of the work or object treated makes contact successively with the rounded projections of said arms 50, beginning with the one at the extreme left in Fig. 4, and moving them one after another to the right, or to the position indicated in Fig. 5, thus permitting the advance of the carriage while maintaining support for that side of the work away from the work-rest or bar 4 and next to the governing or regulating wheel. In this way the work is adequately and accurately supported during its entire inward travel, and until the work has been carried as far as the grinding is to be erformed. On the backward movement ol) the carriage, which takes place when the grinding has been completed, or practically completed, the arms 50, freed by the bar 35, successively swing to their supporting position, or from the dotted line position to the full line position of the extreme right-hand arm, as seen in Fig. 5, thus a ain giving support to the object round uring its complete outward trave It is obvious that instead of swinging horizontally about a vertical pivot, the arms may be arranged to swing vertically about a horizontal pivot, or may be pressed inward toward Athe work b springs and moved in a right-line outwar against springsressure, though the arrangement shown and escribed is found quite satisfactory.

It is found in the grinding of objects by wheels of emery, corundum, carborundum, and the like, which are made up of minute granules or crystals of very hard abrading substances, that some crystals of exceptional hardness will project a minute distance fur- -ther from the body of the wheel than others,

and thatmarks will be made thereby on the object ground. It is hence desirable to impart to the work a short axial reciprocation preparatory to or during withdrawal of the work. This is found to be quiteeective in the removal of such marks, and to produce a better finished article.- No material grinding or reduction of the object treated will be voccasioned by such reciprocatory movement,

. because once the object is ground to the dilnot su jected to sulicient ameter` determined by 'the relative adjustment of the grinding and the governing wheels the object will merely rotate but is ressure against the grinding wheel to do urther grinding of any moment.

As seen in Figs. 3 and 4 the carriage 14 is provided with upstanding lugs 57, one of which is tappedto receive screws 58 to bear against and clamp between-the lugs, a stopplate 59, which may be adjusted to overhang the work-rest- 4to' greater or less extent, and to form a stop against which the I leading end of the work shall abut to prevent undue movement in an inward` direction. In other words, the stopA 59 prevents contact with the side face of either wheel,

or if the radial face of such head or enlargement is to be dressed, ita-.prevents such inward movement as would cause undue cutting away of the radial face.

It is to vbe understood that though the parts are here shown arranged to feed the material into the grinding space from the left-hand side of the machine as viewed in the drawings, it may be entered and withdrawn from the op osite side. In other words, parts of the device may be reversed as to their positions and directions of movement throughout, the invention consisting essentially in means for supporting the work preparatory to its introduction into the grinding space, during the tion, and while being wlthdrawn from grinding position.

60 indicates a pan or guard secured to the under side of the carriage, to catch an oil that may fall from the moving parts o the device.

It will be noted that the runways for the carriage are all within the carriage body, andthus housed or protected from grit, cuttings, and other matter that might tend vto wear the runways and balls, or make the carriage support uneven or irregular.

While I have shown and described ball bearings, and refer to use them because of the reduced riction and consequent free movement of the carriage, and further because of the close adjustment and the maintenance-of true running of the carriage with a -minimum of friction which such construction assures, the anti-friction rolls may be omitted. Again, cylindrical, double-cone, or other well known types of rolls may be employed if desired.

inding opera- In the drawings parts such as the Z- The device here described may be em-v ployed in connection with a grinding wheel, and a rest or backing-up device facing the effective grindingsurface and adjustable relatively thereto, but which has no rotary movement; in other words, with asup ort s'uch as is employed with single wheel) or disk grinders.

1. In combination with a grinding machine, a work-feeding device comprising a ixed supporting guide; a carriage mounted and movable upon said guide toward and lfrom the grinding space; a work-rest or srpport secured to and movable with said carriage; means for supporting the outer or trailing end of the work; and-'supports at the side of tlie workaopposite that which is in contact with the work-rest, extending normally into guiding and supporting position relatively to the work but adapted to be forced aside as the carriage and Work ad- Vance, to carry the work into grinding position.

2. In combination with a grinding niachine, a work-supporting carriage movable toward and from the grinding wheel in a plane parallel with the grinding face thereof; a support for the trailing or outer end of the work, and a work-rest or support adapted to cont-act with one side of the work or object, both mounted upon and movable with the carriage; and a yielding support for the opposite side of the work, carried by a fixed support and adapted to be pressed back by the advancing carriage out of contact with the ywork as the latter .enters and passes through the grinding field.

3. In combination with a rotary grinding member, aguiding base or block in substantial alinement with the active grinding surface; a carriage movable upon said base in the direction of the length thereof; a worksupporting bar upon which the work mayr lie, fixed upon and movable with the carriage; and a yielding support in the path of the carriage for retaining the work upon said work-supporting bar while moving to, while in, and while moving from the grinding position, said yielding support adapted to be forced out of the path of the carriage as the latter advances. U

4. In combination with a rotary grinding member a guiding base or block 1n substantial alinement with the active grinding surface; a carriage movable upon said base in the direct-ion of the length thereof; a workysupporting bar upon which the work may lie, fixed upon and 4movable with thefcarriage; and a yielding support in the ath of the ca rriage for retaining the wor upon said work-supporting bar whilemoving to, while in, and while moving from the grinding position, said'yielding support adapted tobe forced out of the 'pathof the carriage as the latter advances,- and to return automatically into said path as the carriage moves away from the grinding member.

l5. Ay device for supporting work to be ground 'and delivering the same into and removing it from grinding position,` comprising a base or support normally fixed 1n position and extending in the direction of or parallel with the effective face of the grindmg member; a carriage movable upon'and in alinement with said base; a work-rest or bar upon and movable with said carriage and serving to support the side of the work toward the grinding member; a second support also mounted upon and movable with the carriage, to support the outer or trailing end of the work; and a series of yielding arms carried by a support independent of the carriage, extending into the path of the carriage or a part movable therewith and into position to support the side of the Work opposite the rest or bar during the travel of the work from a position outside the grindingarea, but adapted to be forced from such position by the carriage as it carries the work to and across the grinding area, and to return automatically to supportingposition as the carriage retraces its movement.

6. In combination with a grinding member, a. carriage movable across the effective grinding face thereof and provided with supports for one side and for the outer end of work to be ground, said supports being capable of adjustment to suit varying sizes and forms of work and of being fixed in such adjustment; and a yielding support for the opposite side of the work, extending normally into the path of the carriage,

but adapted to be moved out ,of said path as the carriage advances, and to return automatically to normal position as the carriage recedes.

7. In combination with a grinding member, a guiding block or bar adapted to be iixed in position and e'xtendin across and parallel with the effective wor ing ace of the grinding member; a carria e mounted upon and movable lengthwise o said guiding block; a work-rest mounted upon and movable with said carriage, and extending upward above the lower line of the Work on the side toward the grinding surface; a supporting post or bracket fixed in relationto the carriage and provided with mov- 4able arms arranged to bear against the side of the work away from the grinding surface but capable of being forced from such position by-tlie advancing carriage; means for restoring said arms to their normal position during recession of the carriage; and

stops to limit the return movement of said arms and to hold them in proper relation to the work.

8..'In combination with a grinding meinber 2, l'aiixed guiding and supporting block or member 9; a carria 14 mounted u on and ,encompassing said guiding mem er and 'movable longitudinally thereon; a

work-supporting bar 4 carried by lsaid carriage and removably attached thereto; a bar 35 secured u on and movable with the carriage; an en support 33-34 for the work, 'also mounted upon and movable with the carriage; a series of movable arms 50 extendin normally into the path of the bar 35, an serving to support the side of the work furthest from the effective face of the grinding member; means for adjusting said arms toward and from the Work-supporting bar 4; and means for adjust-ing the bar and the end'support 38-34 to suit objects of different diameters.

9. In a device for supporting objects during grinding-and While moving to and from the grinding` position, the combination of a guiding block or base capable of being rigidly fixed in position; a carriage overlying said guiding block and movable longitudinally upon and relatively to said block; adjustable stop screws for limit-ing and determining the range of movement of said carriage; adjustable Work-supports mounted upon and movable with said carriage for supporting the outer end and one side of the Work; and a yielding support for the opposite side of said work, xed relatively to the carriage, normally extending into the path of the carriage or a part thereof and occupying a position to support the second or opposite side of the Work, said support vcharacter described, a xed base or support,

a carriage encompassing said base, supported and movable thereon, the carriage and the base being provided with raceways and with balls or rollers intermediate said raceivays; Work-supports for one end and side of the Work, mounted upon and movable with said carriage; and a yielding sup port for the opposite side of the work, independent of the carriage and automatically movable from and to supporting position as the carriage advances and recedes.

In testimony whereof I have signed myv name to this specification.

WALTER D. ARCHEA. 

